From the answer:
Hello there, talina , I’ll guide you through uninstalling your
QuickBooks Point of Sale.... Before performing the steps, I recommend creating
a backup file in case you need it for future reference.

From the answer:
Hello there, myservicedynamic , Since you're using a third-party app in processing payments in the field, you need to verify with the app's technical support if there's an issue with there connection to QuickBooks.